Resilient mounting for an outboard motor



Nov. 10, 1959 E. c. KIEKHAEFER 2,911,936

RESILIENT MOUNTING FOR AN OUTBOARD MOTOR Filed June 3, 1955 v 3 Sheets-Sheet 1 INVENTOR. HMH? C. ME/(HAEFE/P Um). M

A 7' TOR/V5 r Nov. 10,1959 E. c. KIEKHAEFER 2,

RESILITSNT MOUNTING FOR AN OUTBOARD MOTOR Filed June 3, 1955 3 Sheets-Sheet 2 fl MEP K/ZZ-KHAEFER /Zi 42M A TTORNEV Nov. 10, 1959 E. c. KIEKHAEFER 2,911,936

RESILIENT MOUNTING FOR AN OUTBOARD MOTOR Filed June 3, 1955 s Sheets-Sheei 3 INVENTOR HMHP (t. KIEKHAEFER EVA M A T TOP/VEV United States Patent P RESILIENT MOUNTINGFOR AN OUTBOARD MOTOR Elmer Carl Kiekhaefer, Cedarburg, Wis.

Application June 3, 1955, Serial No. 513,106

. 3 Claims. .(Cl. 115- 17) This invention relates generally to an outboard motor and more specifically to a resilient mounting therefor which lessens the transmission of vibration shock from the power head and propeller to the motor support and boat.

Heretofore, shock mountings have been developed for cushioning the torque vibration of the power head and propeller unit from the transom bracket and boat. Such mountings, however, do not prevent other types of vibration .from being transmitted tothe transom bracket and boat. Applicants invention provides a novel and improved means .for resiliently suspending the outboard motor unit Comprising the power head, drive shaft. and lower unitto vibrationally isolate the outboard motor unit from the supporting bracketand boat.

It is therefore .an object of the present invention to suspend or .float an outboard motor unit for freedom from torque. vibration without transmitting any .of .such vibrations to the supporting bracket or other support member and thereby to the boat and without in any way interfering with the perfect control of such motor in the course of its pivotal movement for steering.

Another object of the.invention..is to provide novel means for resiliently suspendingthe outboard motor unit within a supporting member. I, p Another. object of the invention is the provision .of novel resilient'means of. simple construction requiring fewer parts and less machining; than prior. known meansfor vibrationally isolating the.outboardrnotorunitfrom the boat and supporting member. v

Another objectof the inventionis to provide a by the supporting resilient means.

. .Another object of the invention is the provision ofnovel resilient means .for suspending the outboardrnotor unit within a supporting member wherein impact resulting fromthe outboard motor propeller striking and obstruction is absorbed by said resilient means. v

Objects and advantages otherthan those set, forth above will be apparent from the following description when read in connection with ,the accompanying drawing',-..in which: Fig. 1 is aside elevation view of a part-ofan outboard motor embodying the invention;

' Fig. 2 is a view in section taken along line 2-2 of Fig. 1;

Fig. 3 is a side elevation viewpartially in section of. the outboard motor structure shown in Fig. 1;

Fig. 4 is a view in .section taken .al ongline. 4-4 of Fig. 3;

Fig. 5 is an enlarged view in section taken along line resilient- 1y suspended outboard motor :unit in whichthe dynamic forcesdevelopedthereby are resisted primarily in shear .the lower end thereof, and attachment means 6 for attaching the outboardmotor 1 pendently to the transom 7 of .a boat, not shown.

2,911,936 Patented Nov. 10, 1959 nection between the tiller arm and the power head.

As shown in the drawings, a preferred embodimentxof the invention is illustrated as applied to an outboard motor .1 comprisinga hollow drive shaft housing 2 forenclosing a drive shaft 5, agear housing 3 or lower unit connected to the drive shaft housing 2 and carrying a propeller 4*at The attachment means 6 constitutingthe support mem- .ber' for the outboard-motor unit, comprises a clamp .bracket 8 having a generally L-shaped swivel bracket 9 pivotably connected at one end thereto by means of a bolt 11 for pivotal movement ina vertical plane. The clamp bracket 8 is shown as a'substantially U-shaped clamp adapted to engage over the upper edge of the transom 7 and carrying a clamping screw 12 at the lower end thereof for engaging theinside of the transom 7 to clamp the transom 7 between the end of the screw 12 and a portion of the clamp .bracket 8. The swivel bracket 9 is provided with a vertically extending bushing 13 in register with aligned annular bosses 14 provided in a yoke member 16 and is pivotably connected thereto for pivotal movement in a horizontal plane by means of a hollow .pivot pin 17 passing through the annular bosses 14 and bushing 13 and secured to the bosses 14 by means of a press fit. The yoke member 16 is shown in Figs. 1 and 2 as a vertically extending member having a generally U-shaped cross section throughout, and constitutes a part of the attachment means 6. The yoke member 16 is provided with vertically spaced transverse openings 18 as shown, in Fig.4 in each 'side of the U-shaped member 16 with the corresponding openings of eachside being transversely aligned for a 'purpose to be explained hereinafter.

The hollow drive shaft housing 2 is shown in Fig! 1 form of an'arrow-head as shown in Figs. 2 and 5 with;the rear portion 27 thereof'being streamlined to reduce-the water resistance of the housing 2 While moving through .the water. The front portion 28 ofthe housing 2 :facing .the attachment means 6 forms a substantially U-shaped member complementary to the U-shaped inner surface of the yoke-member- 16.

The front portion 28 of the. drive shaft housing 2 is disposed within the U-shaped yoke .member 16 and attached thereto and spaced therefrom by means of .resilient members shown as .discs 29. The resilient ,discs 29 are shown as circular rubber members although any resilient" material having properties and characteristics similar to the rubber may be used. The rubber members 29 are-preferably firmly secured between a pair of flat 1 circular plates 31 by bonding or any other suitable means.

The sides of the U-shaped front portion 28 of'the drive shaft housing '2 are provided with-transversely aligned circular recesses 32 as shown in Fig. 4 into which one of the plates 31 of the .resilient disc 29 is disposed.

In assembly, the drive shaft housing 2 is connected to the yoke member 16 by disposing the front portion 28 of the drive shaft housing 2 within the yoke member 16 with the circular recesses 32 of the front portion 28 in register or alignment with the corresponding opening 18 of the yoke member 16 as shown in Fig. 4. The resilient discs 29 are then inserted through the openings 18 in the yoke member 16 with the circular plates 31 of the resilient discs 29 mating with the circular recesses 32 of the housing 2. A clamping means, such as a U-clamp, is used to compress the resilient discs 29. The resilient discs 29 are locked in place by means of snap rings 33 shown in Figs. 4 and fitting into corresponding annular grooves 34 provided in the yoke member 16. The

streamlined contour of the housing 2 and yoke member 16 is retained by means of caps 36 which are adapted to seat within the openings 18 and present an outer surface generally flush with the outer surface of the yoke member. The caps are secured in place by means of a screw 37 adapted to engage threaded openings in the outer of the circular plates 31. The outboard motor is preferably designed so that the axial centers of the circular recesses 32 of the drive shaft housing 2 and the openings 18 in the yoke member 16 are positioned to lie in a vertical plane containing the center of gravity of'the outboard motor 1 when the outboard motor is in position for normal operation. The center of gravity of the outboard motor unit generally coincides with or is very close to the axis of drive shaft 5 and therefore need not be shown separately in the drawing.

A power head 22, the drive shaft housing 2 upon which the power head 22 is mounted, and the gear housing 3 form an outboard motor unit that is completely suspended within the yoke member 16 of the attachment means 6 by means of the resilient discs 29. Therefore, the weight of this outboard motor unit, the forces developed by the action of the power head 22 and the thrust developed by the propeller 4 are resisted by the resilient discs 29 primarily in shear. The upper portion 23 of the housing 2 has horizontally extending shoulder portions 21 adapted to engage an end of the yoke 16 to provide a stop for limiting the vertical deflection of the resilient discs 29. The rear and front portions 27, 28 of the housing 2 merge to form vertically extending shoulder portions 20 as shown in Figs. 2 and 5 to provide a stop for limiting the horizontal deflection of the resilient discs 29. In order to permit substantially, complete freedom of movement of the outboard motor unit within the yoke member 16, a shift control rod 38 passing through the pivot pin 17 is provided with a suitable flexible connecting member 39 as shown in Fig. 3 extending between the portion of the control rod 38 carried by the yoke member 16 and the portion of the control rod 38 carried by the gear housing 3. Since the outboard motor is provided with a tiller arm 19 mounted on the yoke member 16 for steering and speed control as is well known in the art, a flexibleconnection means 40 similar to the flexible connecting member 39 is provided as shown in Fig. 7 to permit movement of the outboard motor unit relative to the yoke member 16 and tiller arm 19.

The proper positioning and dimensioning of the resilient discs 29 may be readily calculated by resorting to a force-moment diagram as shown in Fig. 6. Assuming that the maximum propeller thrust F acting through the point C is 100 pounds and the lower resilient disc 29 is positioned at B so that the distance S between the upper resilient disc 29 positioned at A and the lower disc at B is equal to the distance S between the lower disc at B and the point C, the forces F and F may be computed as follows:

Taking force moments about the point B:

F pounds Summation of forces in a horizontal plane:

FB=FA+FC F 200 pounds Therefore, for the foregoing assumed fact situation and neglecting the weight of the outboard unit and the torsional forces developed by the power head, the resilient discs 29 positioned at B must be chosen of proper strength characteristics and dimensions to withstand a thrust force of 200 pounds whereas the resilient discs 29 positioned at A need only be strong enough to resist a force of 100 pounds.

Although only one embodiment has been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an outboard motor, a power assembly comprising an engine and an underwater propeller unit and an intermediate housing rigidly connecting the engine and propeller unit and said housing having transversely spaced wall portions, a support member for pendantly attaching the outboard motor to a boat and comprising a yoke mem ber having transversely spaced wall portions corresponding to the wall portions of said housing, said yoke member being adapted to receive the intermediate housing of the power assembly therebetween in spaced relation and with the corresponding wall portions in opposed relation, said wall portions on the support member being provided with transversely aligned openings and said opposing wall portions having corresponding seats facing said openings, a resilient supporting means insertable through each of said openings and having one end thereof interlocked with the corresponding seat on the wall portion of the intermediate housing in alignment with and opposite from said opening, and means to secure the other end of each resilient element relative to the support member and within the opening, said resilient elements constituting the sole connection between the power assembly and support member for carrying the entire weight of the power assembly and the propeller thrust.

2. In an outboard motor, a power assembly comprising an engine and an underwater propeller unit and an intermediate housing rigidly connecting the engine and propeller unit and said housing having transversely spaced wall portions, a support member for pendantly attaching the outboard motor to a boat and comprising a yoke member having transversely spaced wall portions corresponding to the wall portions of said housing, said yoke member being adapted to receive the intermediate housing of the power assembly therebetween in spaced relation and with the corresponding wall portions in opposed relation, said wall portions on the support member being provided with transversely aligned openings and the wall portions on the intermediate housing being provided with recesses in transverse alignment with said openings, rt:- silient elements extending horizontally between the opposed wall portions of the housing and yoke member and constituting the sole connection therebetween whereby the entire weight of the power assembly and the propeller thrust are carried by the resilient elements in shear, each of said elements being insertable through the respective openings in the yoke member to place one end thereof in the opposed recess of the intermediate housing, and means provided within said opening to secure the other end of each resilient element relative to the yoke member.

3. an outboard motor, a power assembly comprising an englne and an underwater propeller unit and an intermediate housing rigidly connecting the engine and propeller mm and said housing having transversely spaced 5 wall elements, a support assembly for pendantly attaching the outboard motor to a boat and comprising a yoke having transversely spaced members corresponding to the side walls of said housing, said yoke being adapted to receive the intermediate housing of the power assembly therebetween with the walls of the housing in opposed relation and spaced inwardly from the corresponding members of the yoke, said yoke members being provided with transverse openings, resilient means insertable through each of said openings in the yoke, means interlocking the 10 inner end of said resilient means and the corresponding wall of said housing, and means to secure the outer end of each resilient element relative to the support assembly.

References Cited in the file of this patent UNITED STATES PATENTS Karey Sept. 23, Stitz Jan. 23, Butterfield Jan. 15, Wilson Oct. 31, Irgens Sept. 8, Irgens et al. Apr. 3,

FOREIGN PATENTS Italy Mar. 22, Great Britain Oct. 6, 

